The amount of Multicast traffic has seen strong increases over the past few years. IP Multicast provides a method of using an Internet Protocol (“IP”) address to transport data to multiple destinations using a single IP packet. Multicast is often more efficient than unicast or broadcast for one-to-many delivery of data.
Medium Access Control (MAC) is a protocol that may be used to provide layer 2 transmission functionality. An Ethernet MAC frame may encapsulate higher layer payload data by adding a 14 octet header before the data and appending a 4 octet CRC after the data. The header may include a destination MAC address, which may indicate whether the frame contains multicast traffic.
The deployment of large scale switched Local Area Networks (LANs) has also seen significant recent growth. Switches may forward packets by retrieving the destination MAC address from the MAC header. However, if such a header includes an indication of multicast traffic, the frame may be multicast to more ports on the LAN than necessary, which can overwhelm the network. The IEEE 802.1Q and 802.1D standards define the operation of bridges and methods of MAC switching which provide for bridged Virtual LANs (VLANs). While such standards may alleviate some problems related to multicast flooding, there remains a need in the art for improved methods of switching multicast data traffic.